When writing user information on a record carrier using a scanning radiation spot, it is in general desirable to know the position of the radiation spot on the record carrier. Since user information is not available on a virgin recordable record carrier, the position may be determined by reading position information stored in an embossed wobbled grooves or embossed pits of the record carrier.
In general, a track is a line on the record carrier to be followed by a scanning device and has a length of the order of a characteristic dimension of the record carrier. A track on a rectangular record carrier has a length substantially equal to the length or width of the record carrier. A track on a disc-shaped record carrier is a 360.degree. turn of a continuous spiral line or a circular line on the disc.
A track may be a groove and/or a land portion between grooves. A groove is a trench-like feature in a land portion of the recording layer, the bottom of the trench being nearer to or further away from the light-incident side of the record carrier. User information may be recorded on the lands or in the grooves. The pits may be located on the lands or in the grooves.
A record carrier according to the preamble is known from European patent application no. 0 800 165, which discloses an optical record carrier having a groove radially wobbled at a constant frequency without phase jumps and pits formed at predetermined positions between turns of the wobbled groove. The pits are at positions where the wobble has a minimum or maximum deviation as measured from the centre of the pits. The inventors recognized that a of known record carriers is that the reliability of the detection of the pits reduces when user information is recorded in the tracks.